Watt, Why & How e-Newsletter

Put a Stop to Ice Dams

Ice dam

Ice dams are one of many challenges that homeowners face during the winter months. As the name implies, an ice dam occurs when a thick ridge of ice forms at the edge of the roof, building up along the eaves. This buildup of ice prevents melting snow from draining off the roof as it should. When this occurs, water could leak into the home, causing everything from warped floors, walls and ceilings to soggy attic insulation—the perfect environment for mold and mildew.

How it happens

Ice dams form when heat collects in the attic and warms up portions of the roof, but not the eaves. Snow begins to melt on the warm roof, but then it freezes when it reaches the cold eaves. A dam forms, water backs up behind it, and then it flows under the shingles and into the house. When icicles form along the edges of your roof, it's often the sign of an ice dam problem.

What causes the roof to warm up in certain areas and stay cold in others? The answer is fairly simple: Heat traveling from the house to the roof. This can take place via conduction, which happens when heat travels through solid; convection, or rising air; and radiation, which is the transfer of heat through electromagnetic waves. Let's take a closer look:

  • Conduction: Heat moves through the house by conduction through the slanted portion of the ceiling where there may not be adequate space for insulation.
  • Convection: Because insulation is warmer along its top surface, the air above that surface rises and transfers the heat by convection to the roof.
  • Radiation: The temperature along the top surface of the insulation is higher than the temperature of the roof sheathing, and that transfers heat outward by radiation.

Heat is transferred via leaks in the attic, through exhaust systems in the kitchen or bathroom, and through wood stoves and fireplaces, to name a few.

What you can do

If the problem occurs before you've had a chance to take preventive measures, use a roof rake to carefully remove the snow from your roof. It's important to use a proper rake that won't damage your shingles. If water is leaking into your house, create channels in the ice dam that make it possible for water to drain off the roof. Remember, ice dam prevention begins with controlling the loss of heat from your home and keeping your entire roof the same temperature. Here's how: 

  • Increase ventilation in the space between the insulation and the roof sheathing to carry away any heat that leaks through.
  • Add insulation to your living space to prevent the conduction and convection of heat through the ceiling.
  • Seal any areas where warm air may leak from your living spaces into the attic.

More From APCO

Sign Up Now Pay Online for Free with Paperless Billing

Pay Online for Free with Paperless Billing

Learn more

Download our new app

How We Restore Power Learn more

How We Restore Power

Learn more Create Your Own Emergency Outage Kit

Create Your Own Emergency Outage Kit

Visit AEP.com
Use of this site constitutes acceptance of the AEP Terms and Conditions. View our Privacy Policy. © 1996-2019 American Electric Power. All Rights Reserved.

Privacy Policy

Privacy Policy for Appalachian Power, a unit of American Electric Power (AEP)


This Privacy Policy applies only to AppalachianPower.com and the Appalachian Power customer mobile app (com.aep.customerapp.apco). Other AEP websites and apps may be governed by their own privacy policies, appropriate to the uses and needs of each. Throughout the site or app, we may provide links to resources and sites that are not part of AppalachianPower.com or the Appalachian Power customer mobile app. This Privacy Policy does not apply to those resources and sites.


By using this site or app, you consent to the terms of this Privacy Policy. Whenever you submit information via this site or app, you agree to the collection, use, and disclosure of that information in accordance with this Privacy Policy.

Information Collected

  1. Passively collected information

    During your use of this site or app, we may collect anonymous information about your visit here through the use of server logs, cookies, scripts, tracking pixels and other Web traffic tracking systems. This information is aggregated and used to improve user experience through analysis of user activities. This information is never combined with any of the personally identifiable information you may provide in your use of the features of this site or app.
  2. Personally identifiable information

    On certain forms of this site or app, you may be asked to provide information about yourself or your account with us, either to identify yourself to us or to request a service from us. In each case, we will inform you what information is provided at your option and what information is required to complete the transaction or activity you are engaged in. If you are unwilling to provide this required information, you will be unable to complete the requested transaction.

Use and disclosure of information

The information you provide to us will be used to respond to requests you may make for services. Some or all of this information may be added to your permanent account record and may be used for research purposes.

In addition, we may use elements of this information in the following situations:

  1. We may transfer the information to Appalachian Power’s affiliates and subsidiaries, unless such transfer is prohibited by law;
  2. We may transfer the information as part of a merger, consolidation, acquisition, divestiture or other corporate restructuring (including bankruptcy);
  3. We may make the information available to third parties who are providing the product, service or information that you have requested (but not your password);
  4. We may make such information available to third parties who are providing services to Appalachian Power (for example, providing the information to third parties performing computer-related services for Appalachian Power);
  5. We may use the information to communicate with you about products and services that may be of interest to you.
  6. We may disclose the information if we form a good-faith belief that disclosure of such information is necessary to investigate, prevent, or take action regarding any illegal activities or regarding interference with the operation of our site or violation of its terms of use; or
  7. We may disclose the information if we believe that disclosure is required by law or regulation or in response to a subpoena or other order of a court or other governmental agency.

Appalachian Power uses Flurry Analytics Service (provided by Yahoo) in order to improve its mobile apps. Flurry’s privacy policy governs the use of this information.

Also, Appalachian Power reserves the right to share any aggregated information (i.e., non-personally identifiable information) with any third parties for any reason, unless prohibited by law.

We will not sell, rent or otherwise disclose the information we gather about you or your account to any third party, except as outlined in this Privacy Policy.


Appalachian Power takes reasonable steps to protect your personally identifiable information as it is transferred to us, through the use of Web technologies such as the Secure Sockets Layer and others. However, no Internet transmission of information is ever completely secure or error-free. In particular, e-mail sent to or from Appalachian Power may not be secure.

How to Reach Us

If you would like to update your personally identifiable information or if you have questions about this privacy policy, please contact us.

Changes to This Policy

Appalachian Power reserves the right to change this Privacy Policy at any time. If this Privacy Policy changes, the revised policy will be posted to this site. Please review this Privacy Policy before you provide any personally identifiable information through this site. Use of our web site after the posting of a revised privacy policy constitutes your consent to the revised policy.

This policy was last revised on December 13, 2017.

Close ×

Sign Up For Alerts

Subscribing to APCO alerts gives you instant notification for:

  • Billing & Payments - avoid late payments and disconnection
  • Outage Updates - find out if there's an outage at your address and when power will be back on

Win an Xbox One with Alerts!

Enroll in alerts to be eligible to win. Subscribing to I&M alerts gives you instant notification for:

  • Billing & Payments - avoid late payments and disconnection
  • Outage Updates - find out if there's an outage at your address and when power will be back on

Loading video...